Polygons, voxels, SDFs... what will our geometry be made of in the future?

Discussion in 'Rendering Technology and APIs' started by eloyc, Mar 18, 2017.

  1. Vil

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    By the way I've played Nex Machina a little already and it is soooo much fun!
     
  2. Infinisearch

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    My guess would be because the art pipeline would be totally different.
     
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  3. eloyc

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    ...and lazy devs, too scared to leave Mommy Polygon's lap. :-D

    Just kidding. I just hope more devs try this path, create more tools and polish this method. I don't know why but I think that an adventure game or a platformer would look great using SDFs (the way they seem to look now in the games we mentioned, that kind of solid color/crayonesque feeling).
     
  4. milk

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    Its a viable aproach for games that are not targueting a specific look, and are ok with building its art direction side-by-side with its technology and are open to see where that ends up.
     
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  5. Infinisearch

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    Thats not really a voxel though, right? In 3d graphics one of the simplest spatial subdivision schemes is a grid... thats whats going on with a 3d texture. But aren't voxels something specific...and different?
     
  6. milk

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    No.
     
  7. Infinisearch

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    I should be more specific in what I'm saying. Yes its still a grid but in the case of voxels it doesn't contain other 'geometry'. It contains things like color or opacity.
     
  8. Rodéric

    Rodéric a.k.a. Ingenu
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    A pixel is a 2D point with an associated colour
    A voxel should therefore be a 3D point with an associated colour, but it can carry any kind of data really
     
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  9. Magnum_Force

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  10. idsn6

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    On that note, Fairlight's work with particle rendering over the years is notable. Rendering entire scenes with particles allowed for some very cool effects applied directly to the surfaces; attenuating the particle density to simulate depth of field and motion blur was particularly inspiring to me at the time.

     
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  11. Infinisearch

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    I guess what I'm saying is that voxels by definition aren't really meant for spatial subdivision. A uniform grid is the same thing basically and is used for spatial subdivision. I know I'm being a bit anal but I just trying to be accurate in regards to the definition of a voxel.
     
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  12. sebbbi

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    "A voxel represents a value on a regular grid in three-dimensional space."
    https://en.wikipedia.org/wiki/Voxel

    Voxels are commonly used to present stuff like fluid pressure or distance to the nearest surface (signed distance field). Storing color data to voxels is just one of their uses. Similarly a texel (2d equivalent of voxel) can store color data, but it is also commonly used to store stuff like normal vector, material id or distance to closest surface (2d distance field font rendering).

    We store SDF as voxels (volume texture) in Claybook.

    However voxel rendering is an overloaded term. Some people use it to describe blocky looking graphics. Also historically people have also called height-field ray marching as "voxel rendering" (examples: Delta Forces, Comanche, Outcast). These games do not store their data as voxels (3d volume), but instead use a traditional 2d height-field (texels store terrain height at 2d location). These games look blocky, because these terrain height-field ray marchers are using point sampling to get the terrain height at ray location (bilinear filtering was/is expensive on CPU).
     
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  13. London-boy

    London-boy Shifty's daddy
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    Nice! So that's why I see blocky pixellated surfaces on Nex Machina, which makes it look like a low-res render sometimes even though it's clear that it isn't.
     
  14. sebbbi

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    Low res volume texture SDF will actually look more like low poly mesh (planar surfaces) instead of blocks. Unless of course your source data is bad. Many SDF generation algorithms first binary voxelize a mesh (1 bit inside/outside) and then calculate SDF from the binary voxel data. This doesn't maintain sub-voxel distances. Result is similar issues as non-antialiased rasterization (stair stepping lines), because sub-pixel information is lost. This is one reason why low res SDF volume textures might look blocky. Mesh generation could also create blockiness, depending on the algorithm used. Direct ray tracing with trilinear interpolation will look like linear planes instead of blocks... however GPU hardware filtering quality isn't perfect, so it might introduce some errors to ray traced results.

    Good example of hardware texture filtering quality issues: http://www.iquilezles.org/www/articles/hwinterpolation/hwinterpolation.htm.
     
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  15. chris1515

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    Useful for point rendering like Dreams and from a comment into the tweet only available on PS4(Xbox One?)


    But not only

     
  16. eloyc

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    I only see "Loading tweet..." and nothing loads.

    Could you please post the contents other way?

    Thank you!
     
  17. chris1515

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    Brian Karis(Epic) want 64bits atomics to be part of Direct X and Vulkan probably for personal experiment. It is useful for point rendering like in Dreams, small tris and REYES micropolygon style rendering everywhere it is possible to beat the hardware rasterizer.

    For the moment it seems it is only available on PS4.
     
    #57 chris1515, Oct 4, 2017
    Last edited: Oct 4, 2017
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  18. eloyc

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    I already posted this in the game's thread but I would like to comment on the tech side, regarding geometry. How can't this or similar techniques be the future, versus polygons? I was amazed during the whole video, how he copied and pasted so many volumes (and at that scale!), and wondered how much would a PS4 last until the lag showed up if it were polygons that this game were made of. :-D

    If we have this amazing thing up and running, I'm sure the tech can improve over time and catch up with the standards found in polygons/shaders in the areas it may still be lacking (animation, materials, lighting...?).

    Plus, I think that the dreamy art style may mislead or hide some of the real potential as a real all-purpose competitor against polygons, BUT I'm sure that when this game is released and crafty gamers/creators get their hands on it, they will do great things with it.
     
  19. milk

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    Inercia.
     
  20. eloyc

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    What? o_O
     
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